It's not a general thing. It's actually a mini horse. As for fancy horse shoes, yes, the do make rubberized padded horseshoes, but those are generally for horses who spend a lot of time on asphalt, like police horses.
The kids tennis shoes would cover the emtire hoof, preventing dents from the mini tripping and whatnot, and would be ALOT cheaper. A lot. Really, A LOT cheaper. Just standard preformed shoes are expensive. Speciality shoes are obsenely costly.
And horses don't atomatically just kick at anything behind them. If they know its there and are not taken by suprise, it's fine. As with any creature, you have to understand how to move around them with being a threat. It's more about commen sense then anything else.
You are hauling a mini-horse into an area full of people with no common sense who know nothing about horses. I guess that is or should be part of their training.